diff options
Diffstat (limited to 'numpy/random/_examples/cython')
| -rw-r--r-- | numpy/random/_examples/cython/extending.pyx | 78 | ||||
| -rw-r--r-- | numpy/random/_examples/cython/extending_distributions.pyx | 63 | ||||
| -rw-r--r-- | numpy/random/_examples/cython/setup.py | 32 |
3 files changed, 173 insertions, 0 deletions
diff --git a/numpy/random/_examples/cython/extending.pyx b/numpy/random/_examples/cython/extending.pyx new file mode 100644 index 000000000..2a866648d --- /dev/null +++ b/numpy/random/_examples/cython/extending.pyx @@ -0,0 +1,78 @@ +#!/usr/bin/env python +#cython: language_level=3 + +from libc.stdint cimport uint32_t +from cpython.pycapsule cimport PyCapsule_IsValid, PyCapsule_GetPointer + +import numpy as np +cimport numpy as np +cimport cython + +from numpy.random._bit_generator cimport bitgen_t +from numpy.random import PCG64 + +np.import_array() + + +@cython.boundscheck(False) +@cython.wraparound(False) +def uniform_mean(Py_ssize_t n): + cdef Py_ssize_t i + cdef bitgen_t *rng + cdef const char *capsule_name = "BitGenerator" + cdef double[::1] random_values + cdef np.ndarray randoms + + x = PCG64() + capsule = x.capsule + if not PyCapsule_IsValid(capsule, capsule_name): + raise ValueError("Invalid pointer to anon_func_state") + rng = <bitgen_t *> PyCapsule_GetPointer(capsule, capsule_name) + random_values = np.empty(n) + # Best practice is to acquire the lock whenever generating random values. + # This prevents other threads from modifying the state. Acquiring the lock + # is only necessary if if the GIL is also released, as in this example. + with x.lock, nogil: + for i in range(n): + random_values[i] = rng.next_double(rng.state) + randoms = np.asarray(random_values) + return randoms.mean() + + +# This function is declated nogil so it can be used without the GIL below +cdef uint32_t bounded_uint(uint32_t lb, uint32_t ub, bitgen_t *rng) nogil: + cdef uint32_t mask, delta, val + mask = delta = ub - lb + mask |= mask >> 1 + mask |= mask >> 2 + mask |= mask >> 4 + mask |= mask >> 8 + mask |= mask >> 16 + + val = rng.next_uint32(rng.state) & mask + while val > delta: + val = rng.next_uint32(rng.state) & mask + + return lb + val + + +@cython.boundscheck(False) +@cython.wraparound(False) +def bounded_uints(uint32_t lb, uint32_t ub, Py_ssize_t n): + cdef Py_ssize_t i + cdef bitgen_t *rng + cdef uint32_t[::1] out + cdef const char *capsule_name = "BitGenerator" + + x = PCG64() + out = np.empty(n, dtype=np.uint32) + capsule = x.capsule + + if not PyCapsule_IsValid(capsule, capsule_name): + raise ValueError("Invalid pointer to anon_func_state") + rng = <bitgen_t *>PyCapsule_GetPointer(capsule, capsule_name) + + with x.lock, nogil: + for i in range(n): + out[i] = bounded_uint(lb, ub, rng) + return np.asarray(out) diff --git a/numpy/random/_examples/cython/extending_distributions.pyx b/numpy/random/_examples/cython/extending_distributions.pyx new file mode 100644 index 000000000..d17da45c1 --- /dev/null +++ b/numpy/random/_examples/cython/extending_distributions.pyx @@ -0,0 +1,63 @@ +#!/usr/bin/env python +#cython: language_level=3 +""" +This file shows how the to use a BitGenerator to create a distribution. +""" +import numpy as np +cimport numpy as np +cimport cython +from cpython.pycapsule cimport PyCapsule_IsValid, PyCapsule_GetPointer +from numpy.random._bit_generator cimport bitgen_t +from numpy.random import PCG64 + + +@cython.boundscheck(False) +@cython.wraparound(False) +def uniforms(Py_ssize_t n): + """ Create an array of `n` uniformly distributed doubles. + A 'real' distribution would want to process the values into + some non-uniform distribution + """ + cdef Py_ssize_t i + cdef bitgen_t *rng + cdef const char *capsule_name = "BitGenerator" + cdef double[::1] random_values + + x = PCG64() + capsule = x.capsule + # Optional check that the capsule if from a BitGenerator + if not PyCapsule_IsValid(capsule, capsule_name): + raise ValueError("Invalid pointer to anon_func_state") + # Cast the pointer + rng = <bitgen_t *> PyCapsule_GetPointer(capsule, capsule_name) + random_values = np.empty(n, dtype='float64') + with x.lock, nogil: + for i in range(n): + # Call the function + random_values[i] = rng.next_double(rng.state) + randoms = np.asarray(random_values) + + return randoms + +# cython example 2 + +@cython.boundscheck(False) +@cython.wraparound(False) +def uint16_uniforms(Py_ssize_t n): + cdef Py_ssize_t i + cdef bitgen_t *rng + cdef const char *capsule_name = "BitGenerator" + cdef double[::1] random_values + + x = PCG64() + capsule = x.capsule + if not PyCapsule_IsValid(capsule, capsule_name): + raise ValueError("Invalid pointer to anon_func_state") + rng = <bitgen_t *> PyCapsule_GetPointer(capsule, capsule_name) + random_values = np.empty(n, dtype='uint32') + # Best practice is to release GIL and acquire the lock + with x.lock, nogil: + for i in range(n): + random_values[i] = rng.next_uint32(rng.state) + randoms = np.asarray(random_values) + return randoms diff --git a/numpy/random/_examples/cython/setup.py b/numpy/random/_examples/cython/setup.py new file mode 100644 index 000000000..315527a2d --- /dev/null +++ b/numpy/random/_examples/cython/setup.py @@ -0,0 +1,32 @@ +#!/usr/bin/env python3 +""" +Build the demos + +Usage: python setup.py build_ext -i +""" + +import numpy as np +from distutils.core import setup +from Cython.Build import cythonize +from setuptools.extension import Extension +from os.path import join, abspath, dirname + +curpath = abspath(dirname(__file__)) + +extending = Extension("extending", + sources=[join(curpath, 'extending.pyx')], + include_dirs=[ + np.get_include(), + join(curpath, '..', '..') + ], + ) +distributions = Extension("extending_distributions", + sources=[join(curpath, 'extending_distributions.pyx'), + ], + include_dirs=[np.get_include()]) + +extensions = [extending, distributions] + +setup( + ext_modules=cythonize(extensions) +) |